1. Field of the Invention
The present invention relates to an organic electroluminescence (referred to as xe2x80x9cELxe2x80x9d hereinafter) element which serves as a light emitting element.
2. Description of the Related Art
A typical conventional organic EL panel includes a pair of electrode groups and an organic multi-layer body sandwiched between the electrode groups. Each electrode group has a plurality of parallel electrodes arranged like stripes, and the electrodes of the two electrode groups extend perpendicularly relative to each other. The organic multi-layer body includes a plurality of thin layers or films, and at least one of the thin layers is a light emitting layer. The light emitting layer emits a light to display an image when a voltage is applied between the electrode groups.
A so-called simple matrix drive scheme successively scans one of the electrode groups, i.e., either an anode (positive pole) electrode group or a cathode (negative pole) electrode group, while applying a signal voltage to the other electrode group. As a result, desired picture elements (pixels) among those located at intersecting points of the positive and negative pole electrodes radiate and display an image.
Since the simple matrix drive scheme successively displays the image line by line, each of the picture elements is allowed to emit a light for a very short period in a single frame. In order to obtain an image having desired brightness (clarity), therefore, each of the light emitting picture elements should emit a light with a strong instantaneous brightness. If the instantaneous brightness should be increased, a voltage applied to the EL element should be raised during light emission. As a result, a consumption electric power increases. Further, the thin organic films in the light emitting layer may be damaged by heat.
The present invention is directed to an organic EL element suited for use in an organic EL panel, and an object of the present invention is to provide an organic EL element that can emit a light at high-intensity but does not deteriorate light emitting layers greatly. Another object of the present invention is to provide a method of fabricating such an organic EL element.
According to one aspect of the present invention, there is provided an organic EL element including a light emitting portion having an organic thin film and a rectifier portion connected in series to the light emitting portion, wherein the rectifier portion also has an organic thin film, and an electrostatic capacity of the rectifier portion is smaller than that of the light emitting portion.
According to another aspect of the present invention, there is provided a method of making an organic EL element including the steps of forming first and second electrodes independently, forming an organic thin layer diode on the first electrode, forming a lead electrode over the whole of the organic thin layer diode and over at least part of the second electrode, and forming an organic electroluminescence single- or multi-layer body over the second electrode and lead electrode, the organic electroluminescence body including at least one organic electroluminescence light emitting layer.